1. Field of the Invention
The invention refers to a driving arrangement for driving the cutting rolls of a drift advancing machine comprising at least one cutting roll being subdivided in axial direction and being in engagement over at least part of its circumference with the material to be excavated and being movable over the drift face in transverse direction to its axis of rotation.
2. Description of the Prior Art
Such drift advancing machines comprising cutting rolls subdivided in axial direction can, for example, be derived from U.S. Pat. No. 4,253,705. The component parts of such a cutting roll can be shifted one relative to the other in axial direction and to a certain extent, so that a differing width of the cutting roll can be obtained. In these known devices, the cutting rolls are arranged by means of two cantilever arms on a cutting machine, which is, in most cases, movable and may be movable by means of a caterpillar chassis and which may comprise removal conveyor means for transporting away the cut material. From U.S. Pat. No. 3,614,162 there has become known a drift advancing machine comprising cutting means arranged on a swivellable cantilever arm and being driven by a common drive shaft. This shaft is driven by driving motors arranged on the cantilever arm with interposition of reduction gearings.
In such devices the drive motor or drive motors for the rotating drive means for such cutting rolls were coupled one with the other in a force-locking manner, noting that essentially the whole summed-up drive force of the driving motors becomes effective on all component parts of such cutting tools. In practice it is, however, possible that excessive forces become effective on partial areas of the cutting roll during the engagement of such cutting rolls in the rock to be excavated, and in such cases the full driving power becomes effective on that partial areas of the cutting roll, which are subjected to the maximum load. The bearing means and the support means for the cutting roll must, for this reason, be correspondingly designed and it is, as a rule, necessary to use for the purpose of receiving the reactive forces two cantilever arms arranged at a great lateral distance one from the other. The construction and the design of the bearing means must be correspondingly compact and expensive, and such known construction of cantilever arms represent an obstacle for consolidating the drift in proximity of the drift face and also anchoring operations and safety operations at this place.